A Romney victory looks less inevitable after Santorum wins Iowa and Perry pulls out

It's been a day of dramatic developments in the battle to be the Republican party nominee to try to wrest control of the White House from Barack Obama. It started in the early hours with the news that the process of certifying the votes from the Iowa caucuses seventeen days ago had switched the result from Romney with an 8-vote lead to the ex-senator from Pennsylvania winning by 34 votes.

On the day of the election it had been emphasised that the results would have to go through their normal process of certification, and a turnaround like this was always possible.

Great play had been made by Romney supporters of the uniqueness of their man winning the first two states which all added to his momentum and reinforced the notion that his selection was a near certainty.

Significantly, it provides a big boost for Santorum who has also just heard that the certified New Hampshire figures put him ahead of Newt Gingrich in the battle their for fourth place.

Unfortunately for Santorum, the day has also seen the Governor of Texas, Rick Perry, and one-time front-runner, pulling out and throwing his weight behind the ex-house speaker, Newt Gingrich. So the race is now down to four.

On Saturday there is the third primary in South Carolina – a state which in modern times has always chosen the eventual nominee. Polls in the immediate aftermath of Iowa and New Hampshire had Romney with a big lead lead with one putting him 22% ahead.

That is all starting to close, with two of the most recent polls now having Gingrich ahead by 2-3%. It is clear that Newt had a very good debate on Monday night while Romney had a poor one and many are putting the movements down to this.

The story today is not over. Gingrich's second ex-wife, Marianne, has recorded an interview with ABC news which is being shown later tonight. She is reported to have said that this will "end" Gingrich's career. My guess it will add to the interest in Saturday's election and drive a higher turnout.

If Romney does fail to win South Carolina it would mean that instead of him chalking three out of three, as looked likely at the weekend, could be down to just one victory. This battle could last a lot longer than we thought.